Skin science article
Paula's Choice C5 Super Boost Eye Cream Versus Tatcha The Brightening Eye Cream
Paula's Choice C5 Super Boost Eye Cream Versus Tatcha The Brightening Eye Cream This brightening eye moisturizer is formulated around Ascorbyl Glucoside and 3-O-Ethyl Ascorbic Acid to brighten dull-looking skin and soften the look of wrinkles. This brightening
Paula's Choice C5 Super Boost Eye Cream Versus Tatcha The Brightening Eye Cream
This brightening eye moisturizer is formulated around Ascorbyl Glucoside and 3-O-Ethyl Ascorbic Acid to brighten dull-looking skin and soften the look of wrinkles.
This brightening eye moisturizer is formulated around Squalane and Saccharomyces/Rice Ferment Filtrate to brighten dull-looking skin and fade the look of dark spots.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Dicaprylyl Carbonate
Glycerin
Triheptanoin
Ascorbyl Glucoside
3-O-Ethyl Ascorbic Acid
Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer
Arachidyl Alcohol
Cetearyl Alcohol
C13-15 Alkane
Ascorbyl Palmitate
Sh-Polypeptide-121
Acetyl Hexapeptide-8
Hyaluronic Acid
Zerumbone
Bacillus Ferment
Tocopherol
Tocopheryl Acetate
Butyrospermum Parkii Butter Unsaponifiables
Oryza Sativa Bran Extract
Rosmarinus Officinalis Leaf Extract
Helianthus Annuus Seed Oil
Helianthus Annuus Seed Extract
Hydrogenated Lecithin
Cetearyl Olivate
Sorbitan Olivate
Behenyl Alcohol
Arachidyl Glucoside
Propanediol
Butylene Glycol
Cetyl Alcohol
Sodium Phytate
Sodium Citrate
Citric Acid
Sodium Metabisulfite
Phenoxyethanol
Caprylyl Glycol
Ethylhexylglycerin
Hexylene Glycol
Sodium Hydroxide
Water, Dicaprylyl Carbonate, Glycerin, Triheptanoin, Ascorbyl Glucoside, 3-O-Ethyl Ascorbic Acid, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Arachidyl Alcohol, Cetearyl Alcohol, C13-15 Alkane, Ascorbyl Palmitate, Sh-Polypeptide-121, Acetyl Hexapeptide-8, Hyaluronic Acid, Zerumbone, Bacillus Ferment, Tocopherol, Tocopheryl Acetate, Butyrospermum Parkii Butter Unsaponifiables, Oryza Sativa Bran Extract, Rosmarinus Officinalis Leaf Extract, Helianthus Annuus Seed Oil, Helianthus Annuus Seed Extract, Hydrogenated Lecithin, Cetearyl Olivate, Sorbitan Olivate, Behenyl Alcohol, Arachidyl Glucoside, Propanediol, Butylene Glycol, Cetyl Alcohol, Sodium Phytate, Sodium Citrate, Citric Acid, Sodium Metabisulfite, Phenoxyethanol, Caprylyl Glycol, Ethylhexylglycerin, Hexylene Glycol, Sodium Hydroxide
Squalane
Saccharomyces/Rice Ferment Filtrate
Hydrogenated Rice Bran Oil
C15-19 Alkane
Behenic Acid
Dipentaerythrityl Hexahydroxystearate
Glyceryl Stearate Se
Glyceryl Stearate
Beheneth-20
Dimer Dilinoleyl Dimer Dilinoleate
Camellia Sinensis Leaf Extract
Cladosiphon Okamuranus Extract
Angelica Acutiloba Root Extract
Prunus Mume Fruit Extract
Niacinamide
Sodium Hyaluronate
Ferulic Acid
Saccharomyces Cerevisiae Extract
Lecithin
Synthetic Fluorphlogopite
Lysolecithin
Sodium Stearoyl Glutamate
Lysine Carboxymethyl Cysteinate
Xanthan Gum
Stearyl Glycyrrhetinate
1,2-Hexanediol
Caprylhydroxamic Acid
Glyceryl Caprylate
Potassium Hydroxide
Phytic Acid
Silica
Tin Oxide
CI 77891
CI 77491
CI 77492
Water, Squalane, Saccharomyces/Rice Ferment Filtrate, Hydrogenated Rice Bran Oil, Glycerin, C15-19 Alkane, Propanediol, Behenic Acid, Ascorbyl Glucoside, Butylene Glycol, Behenyl Alcohol, Dipentaerythrityl Hexahydroxystearate, Glyceryl Stearate Se, Glyceryl Stearate, Beheneth-20, Dimer Dilinoleyl Dimer Dilinoleate, Camellia Sinensis Leaf Extract, Cladosiphon Okamuranus Extract, Angelica Acutiloba Root Extract, Prunus Mume Fruit Extract, Niacinamide, Sodium Hyaluronate, Ferulic Acid, Saccharomyces Cerevisiae Extract, Bacillus Ferment, Lecithin, Synthetic Fluorphlogopite, Lysolecithin, Sodium Stearoyl Glutamate, Lysine Carboxymethyl Cysteinate, Xanthan Gum, Stearyl Glycyrrhetinate, Caprylyl Glycol, 1,2-Hexanediol, Caprylhydroxamic Acid, Tocopheryl Acetate, Glyceryl Caprylate, Tocopherol, Potassium Hydroxide, Phytic Acid, Silica, Ethylhexylglycerin, Phenoxyethanol, Tin Oxide, CI 77891, CI 77491, CI 77492
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Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Ascorbyl Glucoside (AA-2G) is one of the most stable vitamin C derivatives out there.
It's made by attaching a glucose molecule to ascorbic acid; this glucose "cap" shields the vitamin C from air, light, heat, and metal ions that normally cause pure ascorbic acid to oxidize.
Once on your skin, the enzyme alpha-glucosidase snips off the glucose and gradually releases active ascorbic acid right where it's needed. Basically, it behaves like a slow-release pro-vitamin C with less of a stinging that high-strength ascorbic acid can cause.
The research supports the classic vitamin C benefits as well. In lab and human studies, AA-2G slowed down the skin's production of melanin (the pigment behind dark spots) and helped shield skin cells against sun damage better than ascorbyl phosphate.
These studies also showed AA-2G released vitamin C over a longer period.
A frequently cited manufacturer trial found that a 2% AA-2G face cream significantly improved wrinkle depth and skin roughness after 45 days.
And in 2009, a clinical trial showed it meaningfully lightened dark patches on the gums compared to a placebo.
There's also collagen-synthesis support (since vitamin C is a required cofactor for that) and an antioxidant effect too.
Typical usage is usually between 0.5-5% and most studies/products land around 2%.
AA-2G performs best when formulated at a mildly acidic pH (~5-7) which is much gentler than the pH that pure vitamin C demands (~2.5-3.5).
Just one thing worth knowing: the in-skin conversation rate is only about 55-60% by weight. So a 5% AA-2G product delivers roughly 2.75-3% of actual active vitamin C. On top of that, skin absorption is relatively low because the ingredient is water-soluble.
Bacillus Ferment is created by fermenting Bacillus bacteria with yeast extract and carbohydrates. It acts as a humectant and, depending on the strain, can also provide gentle enzymatic exfoliation.
Depending on the strain and formulation, it may also act as a peptide, probiotic, or prebiotic. Certain strains of Bacillus Ferment help support the skin’s microbiome, soothe inflammation, and promote barrier repair and hydration.
It’s typically used at 0.5-5% concentration, either for mild exfoliation or to improve overall skin health and texture.
Some studies show that Bacillus species can inhibit certain plant fungi (such as Fusarium verticillioides and Fusarium oxysporum) used in agricultural biocontrol. However, these are filamentous molds, not the yeast (Malassezia furfur) responsible for fungal acne.
At this time, there are no studies showing that Bacillus Ferment inhibits Malassezia or that it has been tested on human skin or in cosmetic formulations. Because of this lack of cosmetic and dermatological research, we list Bacillus Ferment as not safe for fungal acne as a precaution. However, it may not trigger breakouts for everyone.
Behenyl Alcohol is a type of fatty alcohol (these are different from the drying, solvent alcohols).
Fatty Alcohols have hydrating properties and are most often used as an emollient or to thicken a product. They are usually derived from natural fats and oils; behenyl alcohol is derived from the fats of vegetable oils.
Emollients help keep your skin soft and hydrated by creating a film that traps moisture in.
In 2000, Behenyl Alcohol was approved by the US as medicine to reduce the duration of cold sores.
Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.
Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.
Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.
Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).
Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.
Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Topically, glycerin does several things at once:
Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.
Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.
This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.
Just know very high concentrations (>40%) can feel tacky in low humidity.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).
It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.
On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.
Another perk of this ingredient is that it stays functional across a wide pH range (3-10).
You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.
Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.
Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.
Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.
Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin.
It’s often used to:
Propanediol is not likely to cause sensitivity and considered safe to use. It is derived from corn or petroleum with a clear color and no scent.
Tocopherol is a fat-soluble antioxidant known as Vitamin E.
You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells.
Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes.
It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks.
This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage.
This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there.
In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading.
Concentrations usually range from 0.1-1% in most leave-on products.
Tocopheryl Acetate is a stable, shelf-friendly form of vitamin E.
Formulators love it because plain vitamin E oxidizes quickly once it hits air. This acetate version stays stable and resists going off, helping to extend a product's shelf life.
It's actually inactive on its own and works like a slow-release "storage" form; the enzymes in your skin called esterases gradually convert it into active vitamin E over time.
One in vivo study showed 5% of the acetate in the living layer of the epidermis converted to vitamin E after 5 days of application. This study also found the skin gained protection against UV damage even though the conversion was slow and small.
Once converted, vitamin E acts as a skin's main fat-soluble antioxidant that fights free radicals to protect skin from damage.
Topical vitamin E generally boosts the skin's photoprotection, and it reduced UV-damage in animal models.
Overall, it has a pretty solid safety profile and has been found to be non-irritating and non-comedogenic. Allergic reactions may happen but stay rare due to how widely the ingredient gets used.
The concentration will vary depending on the formula; industry data shows 0.1% in baby lotions, 3% in lipsticks, and 5% in foot powders. You can also find this ingredient at 100% in a pure vitamin E oil.
Most leave-on skincare keeps it at the lower end, often between 0.5-1%.
Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!